This invention relates generally to teat dip applicators and backflushing systems for dairy animal milker units, and more particularly to automatic milker unit backflushing systems, teat dip applicators, related components, and methods for safely and efficiently applying dips and backflushing milker units.
Dairy milking systems as they relate to the present invention include a cluster of teat cups, each of which is matched with a flexible teat cup liner that is attached to a teat of a dairy animal with a vacuum. Vacuum is applied in pulses between the shell and liner to facilitate movement of the flexible liner to milk the dairy animals. Milk flows from the cow through each flexible liner and then through a short milk tube to a milker unit collecting bowl assembly, which collects milk from all of the animal's teats. This combination of elements is known as a milker unit and can be used to milk cows, sheep, goats and other dairy animals. Each milker unit is used to milk multiple animals so it must be sanitized, at least periodically, to prevent transmission of dirt and germs into the milk, and to help prevent transmission of diseases from animal to animal.
Milk from individual animals flows from each collecting bowl assembly through a long milk tube and into a milk line that receives milk from all of the milker units in the dairy. The milk is then chilled and stored in a milk tank. The milk lines and storage systems must not be contaminated with dirt, debris, chemicals, pathogens, or contaminated milk.
Various methods have been used to clean milker units. For example, milker units have been immersed into a bucket filled with a disinfectant solution for cleaning. In a simple automated variation, milker units are pulled through a so-called “disinfection trough” or multiple troughs filled with disinfectant solution. Other systems include automatic rinsing that is usually done from the downstream end of the long milk tube and cleans the entire length of the long milk tube as well as the milker unit. This latter method involves very high consumption of water and cleaning chemicals, and can waste milk that is in the long milk tube that is otherwise salable. In all cases, a practically complete removal of the disinfectant solution from the milker unit must take place before it is applied to the next cow, so thorough rinsing and/or backflushing are necessary.
In addition, dairy animal teats have broadened milk ducts after milking that make them especially susceptible to new infection from mastitis pathogens. To combat these pathogens, the teats can be treated with a disinfectant solution that adheres well to the teats and which usually also contains a skin-care component. The application of this disinfectant solution is called dipping and can be done with a hand-held dipping cup into which the individual teats are introduced. Dip can also be applied using manual spray devices and foam applicators. Dipping with a cup is especially labor-intensive, but generally has a better success rate and a lower consumption of dipping solution than manual spraying methods.
Some spraying methods are automated to spray dip from a dipping arm or dipping bar. Automated sprayers are not precise and tend to consume much more dipping solution than manual dipping methods. Other early automatic teat dipping applicator systems applied dip upward from the short milk tube toward the bottom of a teat at the end of milking, but before detachment from the milker unit. This arrangement provided some protection, but it did not coat the entire teat uniformly. See U.S. Pat. No. 7,290,497. Others have suggested automated systems that apply dip to an upper teat portion, but most of these failed to provide: uniform dip coverage on teats; consistent volumes of dip application over time; and protection of downstream milk system components from being contaminated by dip and other chemicals.
In particular, most prior automatic teat dip applicators and milker unit cleaner systems fail to adequately ensure that teat dip compositions and backflushing fluids do not enter the long milk tube and contaminate the dairy milk lines. This problem can be caused by a number of factors, but one possible cause for contamination results from differential pressures that develop in dipping and backflushing devices that are connected to milk lines. Differential pressures between the milk lines, and dipping and backflushing devices can cause seepage even through closed valves and tight seals, so it is difficult to design, build, install, maintain, and use automated teat dip applicators and milker unit backflushing systems that are safe and prevent contamination of dairy systems.
Thus, there is a need to provide backflushing and teat dip application automatically and in a conveniently arranged system that also ensures that the dip solutions and backflushing fluids do not contaminate the dairy system and milk supply.